FLAGSTAFF, Ariz. (AP) - The Interior Department is favoring a proposal to ban new mining claims on 1 million acres near the Grand Canyon for the next 20 years while Republicans in Congress try to block any attempt to limit mining operations in an area known for high-grade uranium ore.

Interior Secretary Ken Salazar indicated his preference during a visit to the canyon earlier this year while the U.S. Bureau of Land Management finalized a study on the environmental, health and other impacts of a ban that was released Wednesday.

"The Grand Canyon is an iconic place for all Americans and visitors from around the world, said BLM director Bob Abbey. "Uranium remains an important part of our nation's comprehensive energy resources, but it is appropriate to pause, identify what the predicted level of mining and its impacts on the Grand Canyon would be and decide what level of risk is acceptable to take with this national treasure."

The publication of the study in the Federal Register this week will trigger a 30-day review after which Salazar will issue a final decision. The other alternatives are to take no action, or to withdraw either 300,000 or 650,000 acres from any new claims.

Republican members of Arizona's congressional delegation have lambasted Salazar's moves to first enact a temporary ban on the 1 million acres in 2009 and to make it more permanent. A ban on the filing of new mining claims would eliminate hundreds of jobs and unravel decades of responsible resource development, the GOP has said. Legislation recently introduced in Congress would prevent Salazar from moving forward.

"Uranium mining in northern Arizona can create jobs and stimulate the region's economy without jeopardizing the splendor and natural beauty of the area, and that's why Arizona's federal, state, and local officials oppose a moratorium on such mining," Arizona Rep. Jeff Flake has said.

At least 3,350 active mining claims exist for all types of hard-rock exploration within the 1 million acres. Most of the claims for uranium are staked in the Arizona Strip, a sparsely populated area immediately north of the Grand Canyon. Uranium deposits there are of higher grade than 85 percent of the world's known uranium deposits, the BLM said.

While environmentalists, American Indian tribes, outdoorsmen and others have zeroed in on the impacts of mining to tourism, and water and cultural resources, Republicans have focused on jobs and the economy.

The BLM said the impact from mining is most significant north of the Grand Canyon, particularly in San Juan County, Utah.

Mining will continue regardless of what Salazar decides. Companies that have valid existing claims can develop them if they can provide sufficient quality and quantity of the resource. By BLM's estimate, 30 mines can operate over the next 20 years without a ban on new mining claims, producing 40,000 tons of uranium and increasing the annual domestic production from 8 percent to 17 percent of current U.S. demand.

Regional employment would increase by about 3 percent under the scenario, while the operations would contribute $23 million a year to federal, state and local governments.

Under Salazar's plan, 11 mines could operate under existing claims and produce 11,000 tons of uranium over 20 years. But governments would lose out on $16.6 million in annual revenue and 465 jobs wouldn't materialize.

The figures released Wednesday are different from those in the BLM's draft study, which did not break down some yearly averages or miscalculated the impacts.

The revised figures for employment in the tourism industry jumped from 10,296 to more than 21,000. The BLM said the new figure reflects tourism jobs tied to national parks, monuments and other recreation areas near the Grand Canyon, not national ratios that are primarily weighted by large metropolitan areas.

Salazar's supporters say any increase in mining jobs is not worth risking the health of the Colorado River, damaging lands considered sacred by American Indian tribes or destroying wildlife habitat - all of which could impact tourism.

"The Grand Canyon is an international icon, a biodiversity hotspot and the economic engine for an entire region," said Taylor McKinnon of the Center for Biological Diversity. "Protecting it from further uranium mining pollution is the right thing to do."